// This is the top level collision call for the time step. Here
// all the narrow phase collision is processed for the world
// contact list.
void ContactManager::Collide()
{
// Update awake contacts.
Contact* c = m_contactList;
while (c)
{
Fixture* fixtureA = c->GetFixtureA();
Fixture* fixtureB = c->GetFixtureB();
s32 indexA = c->GetChildIndexA();
s32 indexB = c->GetChildIndexB();
Body* bodyA = fixtureA->GetBody();
Body* bodyB = fixtureB->GetBody();
// Is this contact flagged for filtering?
if (c->m_flags & Contact::filterFlag)
{
// Should these bodies collide?
if (bodyB->ShouldCollide(bodyA) == false)
{
Contact* cNuke = c;
c = cNuke->GetNext();
Destroy(cNuke);
continue;
}
// Check user filtering.
if (m_contactFilter && m_contactFilter->ShouldCollide(fixtureA, fixtureB) == false)
{
Contact* cNuke = c;
c = cNuke->GetNext();
Destroy(cNuke);
continue;
}
// Clear the filtering flag.
c->m_flags &= ~Contact::filterFlag;
}
bool activeA = bodyA->IsAwake() && bodyA->m_type != staticBody;
bool activeB = bodyB->IsAwake() && bodyB->m_type != staticBody;
// At least one body must be awake and it must be dynamic or kinematic.
if (activeA == false && activeB == false)
{
c = c->GetNext();
continue;
}
s32 proxyIdA = fixtureA->m_proxies[indexA].proxyId;
s32 proxyIdB = fixtureB->m_proxies[indexB].proxyId;
bool overlap = m_broadPhase.TestOverlap(proxyIdA, proxyIdB);
// Here we destroy contacts that cease to overlap in the broad-phase.
if (overlap == false)
{
Contact* cNuke = c;
c = cNuke->GetNext();
Destroy(cNuke);
continue;
}
// The contact persists.
c->Update(m_contactListener);
c = c->GetNext();
}
}
void ContactManager::AddPair(void* proxyUserDataA, void* proxyUserDataB)
{
FixtureProxy* proxyA = (FixtureProxy*)proxyUserDataA;
FixtureProxy* proxyB = (FixtureProxy*)proxyUserDataB;
Fixture* fixtureA = proxyA->fixture;
Fixture* fixtureB = proxyB->fixture;
s32 indexA = proxyA->childIndex;
s32 indexB = proxyB->childIndex;
Body* bodyA = fixtureA->GetBody();
Body* bodyB = fixtureB->GetBody();
// Are the fixtures on the same body?
if (bodyA == bodyB)
{
return;
}
// TODO_ERIN use a hash table to remove a potential bottleneck when both
// bodies have a lot of contacts.
// Does a contact already exist?
ContactEdge* edge = bodyB->GetContactList();
while (edge)
{
if (edge->other == bodyA)
{
Fixture* fA = edge->contact->GetFixtureA();
Fixture* fB = edge->contact->GetFixtureB();
s32 iA = edge->contact->GetChildIndexA();
s32 iB = edge->contact->GetChildIndexB();
if (fA == fixtureA && fB == fixtureB && iA == indexA && iB == indexB)
{
// A contact already exists.
return;
}
if (fA == fixtureB && fB == fixtureA && iA == indexB && iB == indexA)
{
// A contact already exists.
return;
}
}
edge = edge->next;
}
// Does a joint override collision? Is at least one body dynamic?
if (bodyB->ShouldCollide(bodyA) == false)
{
return;
}
// Check user filtering.
if (m_contactFilter && m_contactFilter->ShouldCollide(fixtureA, fixtureB) == false)
{
return;
}
// Call the factory.
Contact* c = Contact::Create(fixtureA, indexA, fixtureB, indexB, m_allocator);
if (c == NULL)
{
return;
}
// Contact creation may swap fixtures.
fixtureA = c->GetFixtureA();
fixtureB = c->GetFixtureB();
indexA = c->GetChildIndexA();
indexB = c->GetChildIndexB();
bodyA = fixtureA->GetBody();
bodyB = fixtureB->GetBody();
// Insert into the world.
c->m_prev = NULL;
c->m_next = m_contactList;
if (m_contactList != NULL)
{
m_contactList->m_prev = c;
}
m_contactList = c;
// Connect to island graph.
// Connect to body A
c->m_nodeA.contact = c;
c->m_nodeA.other = bodyB;
c->m_nodeA.prev = NULL;
c->m_nodeA.next = bodyA->m_contactList;
if (bodyA->m_contactList != NULL)
{
bodyA->m_contactList->prev = &c->m_nodeA;
}
bodyA->m_contactList = &c->m_nodeA;
// Connect to body B
c->m_nodeB.contact = c;
c->m_nodeB.other = bodyA;
c->m_nodeB.prev = NULL;
c->m_nodeB.next = bodyB->m_contactList;
if (bodyB->m_contactList != NULL)
{
bodyB->m_contactList->prev = &c->m_nodeB;
}
bodyB->m_contactList = &c->m_nodeB;
// Wake up the bodies
if (fixtureA->IsSensor() == false && fixtureB->IsSensor() == false)
{
bodyA->SetAwake(true);
bodyB->SetAwake(true);
}
++m_contactCount;
}
